Application

Sequence of Operation
Return from Power Failure and Venturi Air Valve Action
34
Siemens Industry, Inc.
Application Note, App 2920
140-1307
2015-07-07
Network Annunciation
If the LCM is connected to a field panel, alarms can be reported using the workstation
software, or by using a printer that is set up in a building manager’s office to receive
alarms. Points in the controller must be entered in the field panel’s point database
(referred to as unbundling) and defined as alarmable. For example, if the room
pressurization alarm (VOL DIF ALM) is unbundled in a field panel and a pressurization
alarm is triggered, an alarm will be annunciated across the network.
Return from Power Failure and Venturi Air Valve
Action
NOTE:
In this section, the phrases Normally Closed and Direct Acting are interchangeable.
Likewise, the phrases Normally Opened and Reverse Acting are interchangeable.
You notify the application whether or not a Venturi Air Valve is normally opened or
normally closed is by setting the point VENTURI ACT to the value that represents the
actions of the air valves connected to the controller.
VENTURI ACT Values.
VENTURI ACT
(value)
Description
0
All Supply and Exhaust Venturi Valves are Normally Closed (Direct
Acting)
1
(default)
Supply Venturi Normally Closed, Exhaust Venturi Normally Opened
2
Supply Venturi Normally Opened, Exhaust Venturi Normally Closed
3
All Supply and Exhaust Venturi Valves are Normally Opened (Reverse
Acting)
NOTE:
If VENTURI ACT is set greater than 3, it will default to 0.
NOTE:
On a return from power failure, the AOs remain OFF for 5 seconds. Therefore, it is
recommended that the Supply Venturi Air Valve be Normally Closed for rooms where
negative or neutral pressurization is required, and Normally Opened for positively
pressurized rooms. Likewise, it is recommended that the General Exhaust Venturi Air
Valve be Normally Opened for rooms where negative or neutral pressurization is
required, and Normally Closed for positively pressurized rooms. Setting of the Venturi
direction is via VENTURI ACT.
Operation of AVS FAILMODE
AVS FAILMODE is an enumerated point that describes how the supply Venturi Air
Valve and the general exhaust Venturi Air Valve will respond if one or both Air Velocity